Modeling milling forces for discrete edge end mills with chip-splitting groove structures

Abstract

Discrete-edge end mills offer superior performance in machining difficult-to-cut materials by discretizing cutting loads via chip-splitting grooves. However, the nonlinear coupling between groove geometry and three-dimensional force dynamics remains poorly understood. This study establishes a physics-constrained parametric design framework for discrete-edge tools. First, a mechanistic cutting force model, incorporating a novel Boolean effective chip-slot function, is developed to rigorously capture the transient engagement caused by geometric discontinuities. The model is validated against milling experiments on AL7075, confirming its capability to predict the characteristic large-amplitude force fluctuations inherent to discrete cutting. Subsequently, a multiobjective optimization strategy is proposed, bounded by structural stiffness constraints derived from cantilever beam theory. Analysis reveals that the groove width (λ₂) significantly modulates the feed force (F_x) through a shearing-dominant mechanism, while the phase offset (ps) governs dynamic stability. Global optimization results demonstrate that the proposed geometric configuration yields a 26% improvement in the comprehensive performance index and a 28.6% reduction in average cutting forces, providing a robust theoretical basis for the precision design of high-performance cutting tools.